Neither Dinara Safina nor Serena Williams has exactly cruised into the Australian Open final. Safina defeated Alla Kudryavtseva, Ekaterina Makarova, Kaia Kanepi, Alize Cornet, Jelena Dokic, and Vera Zvonareva. Zvonareva is a tough opponent, but by the time she reached the semifinals, Safina remembered to turn on the big switch, so she was able to deal with her. But if Cornet had had more guts, or Dokic had had a bit more rest, Safina would be in Russia right now, drinking vodka and hitting herself on the head.
Williams defeated Yuan Meng, Gisela Dulko, Peng Shuai, Victoria Azarenka, Svetlana Kuznetsova, and Elena Dementieva. Dulko gave her a good workout in one of the best matches I saw; some people think that if the roof of Rod Laver Arena had stayed off, Kuznetsova might have taken her out. But Williams' real piece of luck came when a bad snack got the best of Victoria Azarenka, who had to retire early in the second set. Azarenka emphatically won the first set, and there was reason to believe Williams might be on her way out. We'll never know, of course, but it is fair to say that both Williams and Safina had some help getting to the final. That isn't a bad thing--it's just pro tennis.
So neither woman is invincible, and each had to more or less scrap her way to the last match. Cliche though it may be, the player who has the most belief is probably the one who will win the Australian Open, given the high level of play that is likely to be involved. It is, of course, easier for most fans to envision Williams possessing the higher degree of belief, and with good reason. There are other factors, too--weather, injury, the crowd, etc.--that come into play. After having the entire crowd against her during her match against Dokic, Safina asked the crowd to back her from that time on. Since she is considered the underdog, she may get her wish, at least during parts of the final match.